How The Maps Are Made

-Williams stares at his email inbox: a solid wall of news alerts from Yahoo and Google. His search terms aren't the usual fare, like "Hilary Duff." They're more like "Tulsa city one-way" – queries that will help Williams track down announcements of road changes reported by local newspapers. Today has been slow, but suddenly he lights up. An email has arrived containing a newspaper report that a particular one-way road segment in northwest Indiana is changing from westbound to eastbound. Sweet!

-GDT acquired detailed aerial photography of major cities. "We could look at a street and see which way cars were parked, even tire rubber going into intersections, and deduce 85 percent of the turn restrictions and one-way attributes,"

-"We've had projects with pizza-delivery companies where we've printed out for them a big wall map of their 30-minute delivery area. The guys mark things that are wrong and send it back to us," says former GDT president Mike Gerling, who now heads Tele Atlas' North American division.